Methacrylate end-capped 3-(2,2,3,3,-tetrafluoropropoxy)propyl, 3-(2,2,3,3,4,4,5,5-octafluoropentoxy)propyl, and 3-(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluorotridecoxy)propyl side chain siloxanes were evaluated for potential use in hydrogels for contact lens application. The preparation of the methacrylate end-capped perfluoro side chain siloxanes was accomplished in two relatively simple synthetic steps. The first step consisted of the acid-catalyzed co-ring opening polymerization of octamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, and 1,3-bis-methacryloxybutyltetramethyldisiloxane, followed by a platinum-catalyzed hydrosilation with the tetrafluoro-, octafluoro-, and dodecafluoro-substituted allylic ethers. The incorporation of the terminal [—CF2—H] functionality had a dramatic effect on the increased solubility of the fluoro siloxane with hydrophilic monomers. Radical bulk polymerization of the methacrylate-capped fluoro side chain siloxanes with hydrophilic monomers, such as dimethylacrylamide and N-vinyl pyrrolidinone, resulted in transparent hydrogels possessing a wide range of water contents, high oxygen permeability, and a low modulus of elasticity.
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K�nzler et al. (1997) studied this question.